Screen.



Patented Apr. 8, I902.

G. W. CROSS.

SCREEN.

(Application flied Feb. 9, 1901,)

NlTF STATES PATENT OFFICE.

GEORGE W. CROSS, OF CARBONDALE, PENNSYLVANIA.

SCREEN.

SPECIFICATION forming part Of Letters Patent No. 697,071, dated April 8, 1902. Application filed February 9, I901. Serial No. 46,665. (No model.)

To all whom it may concern.-

Beitknown thatI,GEORGE W.Gnoss, acitizen of the United States, residing at Carbondale, in the county of Lackawanna and State of Pennsylvania, have invented a certain new and useful Improvement in Screens, of which the following is a description.

The object of the invention is to provide a screen of maximum efliciency for the separation of various materialssuch as coal, ore, gravel, &c.-into various sizes or grades.

Although applicable to screens of all sorts, the invention is particularly adapted for the separation of coal, and its greatest efficiency will probably be realized in its use in connection with the separation of the finer sizes of such material.

Among the objections which have been found to screens heretofore employed is the tendency of the screen surface to become clogged or choked by small particles of the material lodging in the interstices, thereby pre cluding the passage of any portion of the material therethrough. To overcome this obj ection, various means have been resorted to, such as the employment of brushes so mounted as to bear upon the exterior of a circular screen and designed to open the interstices in which particles of material have lodged. In the present invention provision is made for guarding against the clogging or choking of the interstices, so as to increase the efficiency of the screening-surface by maintaining the same at all times operative for the separating operation.

In carrying out the invention I employ eithera continuous perforated plate or jacket or one made up of a series of segments which may be provided with imperforate margins. Such a plate or segment I provide with interstices of suitable size and preferably of greater length than width, such greater length extending transversely of a circular or rotary screen where the invention is employed in a structure of this description. Intermediate Assuming the invention to be embodied in a screen-segment having imperforate margins, the necessary projection of the imperforate portions of the segment between the rows of interstices may be obtained either by bending such portion inwardly toward the axis of the screen, and therefore out of the plane of the imperforate margins, or such portion may be left in the same plane as the imperforate margins and that portion of the screen-plate containing the interstices may be bent outwardly or away from the screenaxis, and therefore out of the plane of the imperforate margins. In either event that portion of the plate in which the interstices are formed will be exposed to the action of the brush or brushes commonly employed upon the exterior of the screen, so that in the rotation of the screen-barrel the same may readily pass into the interstices and free them from such particles as have become lodged therein.

The invention is illustrated in the accompanying drawings, in which- Figure 1 is a perspective View of a portion of a screen-segment embodying myinvention. Fig. 2 is a transverse section on the line 2 2 of Fig. 1. Fig. 3 is a longitudinal section on the line 3 3 of Fig. 1, and Fig. 4 is a longitudinal section on the line 4 at of Fig. 1.

Referring to the drawings, in which similar letters denote corresponding parts, it will be observed that the invention has been illustrated as embodied not in a continuously-perforated screen-jacket, but as embodied in one of the plates or segments A, preferably of sheet-steel or other similar material, with which such a screen-jacket may be built up. This segment, the material of which is of uniform thickness throughout, is provided with end margins at and side margins a. at, either or both of which may be provided with bolt-holes to facilitate attachment of the segment to the screen-frame.

b designates the screening interstices, here shown as of considerably greater length than width and arranged in longitudinal rows or series, the greatest dimension of the interstices extending, however, transversely of the plate. Also, as here shown, the interstices b are arranged in rows not only longitudinally, but transversely. This, however, may, if desired, be so modified as that while such inthe plate.

terstices are in rows longitudinally of the plate only the interstices of alternate longitudinal rows shall be in line transversely of the plate, this arrangement of the mesh being known in the art as staggered.

c designates integral imperforate tumblers formed of those portions of the screen-plate which bound the ends of the elongated interstices b. As here shown, these tumblers c are formed by bending inwardly toward the axis of the screen the imperforate portion of ings as lying out of and above the plane of the imperforate margins of the segment. As heretofore explained, however, they may lie in the same plane as the imperforate margins, but be adapted for the tumbling or agitation I of the material by lying above the surface of thereby rendered such interstices inoperative for separating purposes. This will be more readily appreciated on reference to Fig. 2 of the drawings, from which it will be seen that the imperforate tumblers interpose no obstacle to the passage of the brush or brushes through the entire length of each and every perforation in the screen.

So far as the tumbling operation is concerned this is most efficiently performed by the integral tumblers c,which lying above the plane of the perforate surface of the plate interrupt the stream of material passing over such surface, prevent it from sliding upon thewebs bounding the interstices,and assure They are illustrated in the draw-- the plane of said tumblers,

suchagitation of the mass as that the parti cles designed for separation at the portion of the screen-barrel at which segments of a certain mesh are employed will be prevented from riding upon larger particles and thereby escaping the separating operation.

. What I claim is-- 1. In a screen-surface, a plate of uniform thickness throughout,provided with integral, imperforate tumblers, substantially straight from end to end and interstices each bounded by webs lying in the same plane but out of substantially as set forth. a 4

2. In a screen-surface, a plate of substantially uniform thickness throughout,provi ded with transverse elongated interstices disposed in longitudinal series and having parallel side Webs, and integral, imperforate tumblers between said series, said tumblers being substantially straight from end to end and arranged out of the plane of said webs, substantially as set forth.

3. In a screen-surface, a plate of uniform thickness throughout, provided with interstices arranged in longitudinal series, the imperforate material of said plate between each series being straight and continuously elevated above the webs bounding the said in-' GEORGE w. CROSS.

Witnesses:

E. D. YARRINGTON, J. R. VANDERFORD. 

